Pipe, method for production thereof and corresponding tool

Abstract

A pipe includes a base body ( 8 ) of metal, defining an outer surface ( 10 ) of the base body and an inner surface ( 12 ) of the base body, and an inner coating ( 14 ) which is applied to the inner surface ( 12 ) of the base body. The inner coating ( 14 ) includes a thermoplastic material or a polyamide. The pipe may be used in the transport of drinking water.

1. Pipe comprising:
 a hollow base body formed of metal, defining an outer surface of the base body and an inner surface of the base body, and 
 an inner coating which is applied to the inner surface of the base body, 
 wherein the inner coating is constituted by a composition consisting of a thermoplastic material and an acrylic material, and 
 the thermoplastic material is based on polyolefines or based on polyamide. 
 
     
     
       2. Pipe according to  claim 1 , wherein the inner surface is obtained by hammering. 
     
     
       3. Pipe according to  claim 1 , wherein the base body is formed of cast iron. 
     
     
       4. Pipe according to  claim 3 , wherein the base body has a mean wall thickness of less than 4 mm. 
     
     
       5. Pipe according to  claim 3 , wherein the base body is formed of spheroidal graphite iron. 
     
     
       6. Pipe according to  claim 1 , wherein the inner coating comprises a contact surface for a food substance passing through said pipe. 
     
     
       7. Method for producing a pipe, the method comprising;
 forming a hollow base body of metal, to define an outer surface of the base body and an inner surface of the base body; 
 processing said inner surface; and 
 applying an inner coating to the inner surface of the base body, 
 wherein the inner coating is constituted by a composition consisting of a thermoplastic material and an acrylic material and the thermoplastic material is based on polyolefines or based on polyamide; and 
 said processing step includes: 
 a) removing rough portions from an unprocessed inner surface of the base body, thus obtaining an inner surface which is partially drilled, the step of removing the rough portions being carried out by partial drilling of the unprocessed inner surface; and 
 b) at least partially removing a layer of oxide on the inner surface by an oxide removal operation, to obtain a processed inner surface prior to application of said inner coating. 
 
     
     
       8. Method according to  claim 7 , wherein:
 the applying the inner coating comprises projecting solid particles of coating onto the inner surface of the base body and, 
 the method further comprises: 
 before the applying the inner coating, heating the base body to a fusion temperature of the coating particles. 
 
     
     
       9. Method according to  claim 7 , further comprising:
 before the removing the rough portions, producing the base body from cast iron. 
 
     
     
       10. Method according to  claim 9 , wherein the base body is produced from spheroidal graphite iron. 
     
     
       11. Method according to  claim 7 , wherein the oxide removal operation is hammering. 
     
     
       12. Method according to  claim 11 , further comprising:
 before the applying the inner coating, removing drilling and hammering residues by suction or blowing.